This invention relates to a magnetic device for converting the intrinsic magnetic force of permanent magnets into a useful torque. The unit torque is derived basically from a three-pole permanent magnets configuration consisting of two elongated bar magnets each having opposite magnetic polarities on two broad side surfaces divided by a longitudinal plane; one of the bar magnet is referred to as the movable magnet and the other bar magnet is referred to as the stationary magnet and located juxtaposed and perpendicular to a broad side surface of the first bar magnet having a single magnetic polarity. A torque is developed by the interaction between the north and south polarities at the end of the stationary bar magnet facing the single magnetic polarity of the broad side surface of the movable bar magnet to cause the movable bar magnet to move in its longitudinal direction relative to the stationary bar magnet. A plurality of such three-pole permanent magnets configurations may be provided around the periphery of a rotary wheel to provide a continuous rotary torque. Such configuration of converting intrinsic magnet force of permanent magnets to useful torque output has not heretofore been achieved.